AbstractSpindles experience problems related to increased power and velocity, and can have very high power consumption. The work reported here is aimed at improving design methods for high‐performance spindles and machine‐tool bearings, and is aimed at determining the influence, of the oil quantity supplying the contact, on power consumption and on contact temperature. A finite element program, TACT, can efficiently predict power loss and the thermal state of machine‐tool bearings, and the remaining unknown in these thermo‐piezo‐viscous‐elastic (TPVE) calculations is inlet oil film height. The authors address this problem and, within the context of this work, develop a high‐speed ISO 50 spindle which has a thin‐wall bearing housing, and is ‚thermally tuned‚, so avoiding thermal instability, while the preload stays constant. Its experimentally determined power consumption values agree well with the TPVE prediction for an assumed inlet fi